Christopher A Viehbacher, CEO of S-A described the acquisition as an "important milestone" for the future of S-A.

He said: "Combined, our two companies will bring tremendous expertise, commitment and resources to biotechnology, particularly in rare diseases, along with similar cultural traits, including patient-centric missions and strong commitments to the communities we serve."

S-A also announced a subsequent offer period beginning today (April 4) to allow remaining Genzyme shareholders who had not tendered their shares already the opportunity to do so. This offer expires on Thursday April 7.

Shares of common stock not tendered by this stage would be cancelled and converted into the right to receive $74.00 per share in cash and one CVR per share.